Detective Constable Peter Spiers, investigating, said: “I am appealing for anyone who saw three men or the black BMW 3 Series in the area around the times stated to get in touch as you may have vital information that could help our investigation.

“I would also like to speak to anyone who may have been offered the jewellery, pictured, for sale.

“I’d like to take this opportunity to reassure the local community that crimes of this nature are extremely unusual in Kings Langley and we are doing all we can to find these offenders.